The present invention relates to an optical pickup, within an optical disc apparatus for reading out or recording information recorded from/onto a recording surface of an optical disc, and it further relates to the optical disc apparatus comprising the same therein.
An optical disc apparatus for recording information onto a disc-like recording medium or reading out the information recorded thereon, for reproducing, since it is able to record the information of a relatively large amount or volume thereof on the optical disc, and also since the medium can be handled easily because of a large rigidity thereof, is used widely, as an external recording device for a computer and/or a recording apparatus for audio/video.
In such the optical disc apparatus, a mechanism for driving a lens, which focuses or diverges lights from a light emitting element, in an optical axis direction thereof, is a lens actuator. In general, the lens actuator is made up with a lens, a moving part including a holder for holding the lens thereon, a supporting member(s) for supporting this moving part, and a driving portion, such as, a motor, etc. Supplying drive current to the driving portion, such as, the motor, etc., allows driving the moving part. This lens actuator also includes means for correcting or compensating a spherical aberration, which is caused due to unevenness of the thickness of a transparent protection layer of the optical disc and/or movement between recording layers of a multi-layered recording disc.
In recent years, advancements have been made on high-density of the optical disc, and as a method for dealing with this is achieved by, mainly, shortening is made on the wavelength of a laser, as the light emitting element, or widening is made an aperture of an objective lens. Such high-density optical disc, since the spherical aberration mentioned above results into deterioration of signals, which are recorded or reproduced, then there is a necessity of a means or device for compensating that spherical aberration. For the purpose of compensating a large spherical aberration, a lens drive width of the lens actuator is set to be large, and further as the objective lens is applied a lens having a short focus distance.
In recent years, a demand is increased, in particular, for an optical disc apparatus, being smaller and thinner in sizes thereof, and for this reason, it is necessary to arrange each of parts thereof, in the optical disc apparatus, effectively, within a limited space thereof. With the following Patent Document 1, a lens actuator and an objective lens actuator are disposed to align vertically, in a focusing direction, i.e., in a normal direction of the optical disc surface.
[Patent Document 1] Japanese Patent Laying-Open No. 2003-338069 (2003), see FIG. 1 thereof.